The invention relates to an inductive transmitter, in particular a rotating transmitter, for signal and energy transmission between moving components.
Especially when used in a motor vehicle, such a transmitter should permit for example, bi-directional data transmission between the steering column and the steering wheel, with simultaneous energy transmission from the steering column to the steering wheel. The transmission of energy can be approximately 1 W if only the steering wheel electronics need to be supplied, with an additional 120 W if a steering wheel heater must be supplied as well. Moreover, it is also possible for information to be exchanged regarding the activation of the horn, control buttons for driving comfort, a telephone dialing button, speed regulation (cruise control), certain radio functions, or even monitoring or activation of the air bag.
Conventionally, in such cases, a coiled spring is provided for data transmission and/or a slip ring for energy transmission. However, the coiled spring and slip ring tend by nature to have a relatively high noise level and, at the same time, cause a multitude of problems, such as so-called EMC problems (EMC=electromagnetic compatibility), installation and repair problems, as well as a non-negligible amount of friction and difficulty in producing contact. If the inductive transmission of electrical energy is executed at the same time as data transmission, this may result in cross-talk, particularly since the transmitter has an efficiency of <0.6 and the internal resistance of the secondary side is >15 ohm.